PURPOSE: Fluvoxamine (FLV) has been used widely as an antidepressant agent belonging to the group of second-generation selective serotonin reuptake inhibitors. However, only one work on the human metabolism of FLV was reported in 1983, examining a human urine specimen, and tentatively identified nine metabolites. Therefore, in the present work, the metabolites of FLV were examined in the liver, bile, and urine from a human cadaver, and the metabolites produced in the human liver microsomes (HLMs) in vitro were also examined. METHODS: Metabolites in each matrix were treated altogether in a tube where impurities had been precipitated using acetonitrile. The identification and tentative quantification of metabolites in human specimens and HLMs were performed using liquid chromatography (LC)-high resolution mass spectrometry (MS), LC-tandem mass spectrometry (MS/MS) and LC-QTRAP- MS/MS. RESULTS: Eleven new metabolites designated as M1 to M11 were detected from human cadaver specimens and HLMs. M1 was produced after acetylation at the terminal NH CONCLUSIONS: To our knowledge, this is the first report on the existence of eleven new metabolites (M1-M11) of FLV in HLMs, human liver, bile and urine. The present eleven metabolites may be useful for the identification of FLV in human samples both antemortem and postmortem.